bisecting fixing commit since a1b977b49b66c75e6c51a515f6700371ae720217
building syzkaller on fa79ed2ae1c546ca48519cfcd80d43b51b502750
testing commit a1b977b49b66c75e6c51a515f6700371ae720217 with gcc (GCC) 8.1.0
kernel signature: c58d104f2153950d12eec1704bf6d3fe180b9ac8badf16f4e6b00788c6877548
all runs: crashed: WARNING: ODEBUG bug in tcindex_destroy_work
testing current HEAD 675cc038067f0e530471c56a7442935f84669d95
testing commit 675cc038067f0e530471c56a7442935f84669d95 with gcc (GCC) 8.1.0
kernel signature: 2118e4f2eb10f4a199070a01c4c7ccdd626da5659d2792037b36a1fc2b6fb9da
all runs: crashed: WARNING: ODEBUG bug in tcindex_destroy_work
revisions tested: 2, total time: 26m52.827265307s (build: 17m56.131060763s, test: 8m16.475760053s)
the crash still happens on HEAD
commit msg: Linux 4.19.167
crash: WARNING: ODEBUG bug in tcindex_destroy_work
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'.
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.5'.
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.3'.
------------[ cut here ]------------
ODEBUG: free active (active state 0) object type: work_struct hint: tcindex_destroy_rexts_work+0x0/0x20 include/net/pkt_cls.h:301
WARNING: CPU: 0 PID: 23 at lib/debugobjects.c:328 debug_print_object+0x168/0x210 lib/debugobjects.c:325
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 23 Comm: kworker/u4:1 Not tainted 4.19.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: tc_filter_workqueue tcindex_destroy_work
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x17c/0x22a lib/dump_stack.c:118
 panic+0x1cd/0x375 kernel/panic.c:186
 __warn.cold.7+0x1b/0x3e kernel/panic.c:541
 report_bug+0x1a4/0x200 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x200/0x350 arch/x86/kernel/traps.c:296
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038
RIP: 0010:debug_print_object+0x168/0x210 lib/debugobjects.c:325
Code: 8b 87 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 92 00 00 00 48 8b 14 dd 60 6b 8b 87 4c 89 fe 48 c7 c7 e0 60 8b 87 e8 9b b6 ea fd <0f> 0b 83 05 ab af f9 05 01 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffff8881f4d1fc38 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000004 RSI: 0000000000000008 RDI: ffffffff8a3e3a60
RBP: ffff8881f4d1fc78 R08: ffffed103ecc3eef R09: ffffed103ecc3eee
R10: ffffed103ecc3eee R11: ffff8881f661f777 R12: 0000000000000001
R13: ffffffff8875a8a0 R14: ffffffff813dccd0 R15: ffffffff878b67c0
 __debug_check_no_obj_freed lib/debugobjects.c:785 [inline]
 debug_check_no_obj_freed+0x252/0x428 lib/debugobjects.c:817
 kfree+0xbd/0x220 mm/slab.c:3821
 tcindex_destroy_work+0x2f/0x80 net/sched/cls_tcindex.c:230
 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2155
 worker_thread+0x85/0xb60 kernel/workqueue.c:2298
 kthread+0x347/0x410 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

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